The present invention is for a new inventive device and method to collect and detect optical fluorescent emissions from a reporter and an analyte. In particular, the present invention is an optical collection device for collecting fluorescent optical emissions at the molecular level, and a method for using the same. The molecular-based optical fluorescence emission detection system is an optical device suitable for sensing the presence of explosive, chemical or biological warfare substances using a chemical warfare indicating chromophore (CWIC) or amplifying fluorescence polymers (AFPs), such as those polymers discussed in U.S. Pat. No. 7,208,122.
Explosive, chemical and biological substances are difficult to detect. One approach for detecting these substances is to use a fluorescence detection scheme. The explosive, chemical and biological substances, called analytes, interact with an innovative fluorescent material such as a CWIC or AFP, and cause changes in the intensity, wavelength, or the duration of the fluorescence signal. The detection of explosive, chemical or biological substances can be achieved by monitoring such changes. One challenge of traditional fluorescence-based detection systems is the low signal-to-noise ratio (SNR). The low SNR may be due to the low fluorescence signal and the presence of excitation light and ubiquitous background noise in the signal collection path.
One focus of current research is to improve the detection of explosive, chemical and biological warfare substances reacting with CWIC or AFP materials by improving optical collection efficiency and noise rejection. As an alternative to traditional fluorescence-based methods, surface plasmon-coupled emission (SPCE) sensors are best suited to collect fluorescing emissions, and provide increased optical SNR and hence sensitivity. Testing has shown that a SPCE sensor arrangement enhances fluorescence signal strength by significantly improving the collection efficiency. Additionally, a SPCE sensor arrangement increases the signal-to-noise ratio via the implementation of forbidden light detection and polarization filtering. The highly p-polarized SPCE signal allows polarization filtering to be used to further improve signal-to-noise ratio. These two advantages enable high sensitivity and low detection limits for the fluorescence-based detection system. However, current optical collection devices for SPCE sensor arrangements are cumbersome and difficult to use.
The need is for a less cumbersome apparatus and method to optically detect the fluorescent emission from an explosive, chemical or biological warfare substance reacting with a CWIC or AFP while having a high signal-to-noise ratio. The requirement is to have a portable apparatus to detect the fluorescent emissions of explosive, chemical or biological warfare samples generated from the reaction of the samples with CWIC or AFP material.